THE BUTTERWORTS 215 



in the case of English specimens of the Common 

 Butterwort, Pinguicula vulgaris, Linn. This species 

 also occurs in Alpine Switzerland (Plate XXXVIII., 

 Fig. 2). In one case Darwin records that 142 insects 

 were caught by 32 leaves, giving an average of 4'4 

 insects per leaf. In addition, the small leaves of a 

 Heath and other plant fragments were often blown 

 by the wind on to the leaf accidentally, to which they 

 adhered. He was also able to show that when 

 objects which contain little or no soluble matter come 

 to rest on the leaves, there is no secretion by the 

 glands. But where the substance is nitrogenous, the 

 secretion is copious, and the material absorbed by 

 the leaf contributes to the food-supply of the plant, 

 and helps to compensate for the limited extent of the 

 root system by which nutriment is derived from the 

 soil. 



The fact that the leaves of the Butterworts contain 

 a special substance was known for some hundred 

 years before Science discovered its true nature. 

 The ancient herbalist, John Gerarde, wi'iting in 1597, 

 says, " The husbandmen's wives of Yorkshire, do use 

 to annoint the dugs of their kine with the fat and 

 oilous juice of the herbe Butterwoort, when they 

 are bitten with any venemous worm, or chapped, 

 risted, and hurt by any other meanes." Kerner also 

 states that a similar use of this plant is made in 

 Switzerland. Linnseus, more than 150 years ago, 

 related that the Common Pinguicula, which is 

 frequent in the Arctic regions as well as in the 



